Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261898AbVEWPus (ORCPT ); Mon, 23 May 2005 11:50:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261905AbVEWPto (ORCPT ); Mon, 23 May 2005 11:49:44 -0400 Received: from fmr18.intel.com ([134.134.136.17]:26299 "EHLO orsfmr003.jf.intel.com") by vger.kernel.org with ESMTP id S261898AbVEWPrZ (ORCPT ); Mon, 23 May 2005 11:47:25 -0400 Message-Id: <20050523154228.761736000@csdlinux-2.jf.intel.com> References: <20050523153906.988390000@csdlinux-2.jf.intel.com> Date: Mon, 23 May 2005 08:39:09 -0700 From: Anil S Keshavamurthy To: akpm@osdl.org Cc: tony.luck@intel.com, rohit.seth@intel.com, rusty.lynch@intel.com, prasanna@in.ibm.com, ananth@in.ibm.com, systemtap@sources.redhat.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, anil.s.keshavamurthy@intel.com Subject: [patch 3/4] Kprobes support for IA64 Content-Disposition: inline; filename=kprobes-jprobes-support.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6413 Lines: 169 This patch adds IA64 architecture specific JProbes support on top of Kprobes signed-off-by: Anil S Keshavamurthy signed-off-by: Rusty Lynch ======================================================================= arch/ia64/kernel/Makefile | 2 - arch/ia64/kernel/jprobes.S | 61 +++++++++++++++++++++++++++++++++++++++++++++ arch/ia64/kernel/kprobes.c | 28 ++++++++++++++++---- include/asm-ia64/kprobes.h | 5 +++ 4 files changed, 89 insertions(+), 7 deletions(-) Index: linux-2.6.12-rc4/arch/ia64/kernel/kprobes.c =================================================================== --- linux-2.6.12-rc4.orig/arch/ia64/kernel/kprobes.c 2005-05-23 07:57:06.490151962 -0700 +++ linux-2.6.12-rc4/arch/ia64/kernel/kprobes.c 2005-05-23 07:57:38.340737509 -0700 @@ -35,12 +35,15 @@ #include #include +extern void jprobe_inst_return(void); + /* kprobe_status settings */ #define KPROBE_HIT_ACTIVE 0x00000001 #define KPROBE_HIT_SS 0x00000002 static struct kprobe *current_kprobe; static unsigned long kprobe_status; +static struct pt_regs jprobe_saved_regs; enum instruction_type {A, I, M, F, B, L, X, u}; static enum instruction_type bundle_encoding[32][3] = { @@ -318,15 +321,28 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) { - printk(KERN_WARNING "Jprobes is not supported\n"); - return 0; -} + struct jprobe *jp = container_of(p, struct jprobe, kp); + unsigned long addr = ((struct fnptr *)(jp->entry))->ip; -void jprobe_return(void) -{ + /* save architectural state */ + jprobe_saved_regs = *regs; + + /* after rfi, execute the jprobe instrumented function */ + regs->cr_iip = addr & ~0xFULL; + ia64_psr(regs)->ri = addr & 0xf; + regs->r1 = ((struct fnptr *)(jp->entry))->gp; + + /* + * fix the return address to our jprobe_inst_return() function + * in the jprobes.S file + */ + regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip; + + return 1; } int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { - return 0; + *regs = jprobe_saved_regs; + return 1; } Index: linux-2.6.12-rc4/arch/ia64/kernel/Makefile =================================================================== --- linux-2.6.12-rc4.orig/arch/ia64/kernel/Makefile 2005-05-23 07:55:50.895426325 -0700 +++ linux-2.6.12-rc4/arch/ia64/kernel/Makefile 2005-05-23 07:57:22.849526761 -0700 @@ -20,7 +20,7 @@ obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o obj-$(CONFIG_IA64_CYCLONE) += cyclone.o obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o -obj-$(CONFIG_KPROBES) += kprobes.o +obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o mca_recovery-y += mca_drv.o mca_drv_asm.o # The gate DSO image is built using a special linker script. Index: linux-2.6.12-rc4/arch/ia64/kernel/jprobes.S =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.12-rc4/arch/ia64/kernel/jprobes.S 2005-05-23 07:57:22.850503324 -0700 @@ -0,0 +1,61 @@ +/* + * Jprobe specific operations + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) Intel Corporation, 2005 + * + * 2005-May Rusty Lynch and Anil S Keshavamurthy + * initial implementation + * + * Jprobes (a.k.a. "jump probes" which is built on-top of kprobes) allow a + * probe to be inserted into the beginning of a function call. The fundamental + * difference between a jprobe and a kprobe is the jprobe handler is executed + * in the same context as the target function, while the kprobe handlers + * are executed in interrupt context. + * + * For jprobes we initially gain control by placing a break point in the + * first instruction of the targeted function. When we catch that specific + * break, we: + * * set the return address to our jprobe_inst_return() function + * * jump to the jprobe handler function + * + * Since we fixed up the return address, the jprobe handler will return to our + * jprobe_inst_return() function, giving us control again. At this point we + * are back in the parents frame marker, so we do yet another call to our + * jprobe_break() function to fix up the frame marker as it would normally + * exist in the target function. + * + * Our jprobe_return function then transfers control back to kprobes.c by + * executing a break instruction using one of our reserved numbers. When we + * catch that break in kprobes.c, we continue like we do for a normal kprobe + * by single stepping the emulated instruction, and then returning execution + * to the correct location. + */ +#include + + /* + * void jprobe_break(void) + */ +ENTRY(jprobe_break) + break.m 0x80300 +END(jprobe_break) + + /* + * void jprobe_inst_return(void) + */ +GLOBAL_ENTRY(jprobe_inst_return) + br.call.sptk.many b0=jprobe_break +END(jprobe_inst_return) Index: linux-2.6.12-rc4/include/asm-ia64/kprobes.h =================================================================== --- linux-2.6.12-rc4.orig/include/asm-ia64/kprobes.h 2005-05-23 07:55:50.897379450 -0700 +++ linux-2.6.12-rc4/include/asm-ia64/kprobes.h 2005-05-23 07:57:38.341714071 -0700 @@ -57,6 +57,11 @@ kprobe_opcode_t insn; }; +/* ia64 does not need this */ +static inline void jprobe_return(void) +{ +} + #ifdef CONFIG_KPROBES extern int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/